1. Field
Example embodiments relate to a composition, a passivation layer, organic thin film transistor, and electronic device including the same, a method of forming the passivation layer and methods of fabricating the organic thin film transistor and electronic device, and, more particularly, to a composition which may include a perfluoropolyether derivative and a photosensitive polymer, or a copolymer thereof, a passivation layer including the composition, an organic thin film transistor including the passivation layer, an electronic device including the organic thin film transistor, method of forming the passivation layer, and methods of fabricating the organic thin film transistor and electronic device.
2. Description of the Related Art
Recently, in the wide fields of electronic devices, and photonic devices, interest in the use of polymer materials as electric and electronic materials has increased because the polymer materials may be more easily molded into a fiber or a film, may be flexible, and may have improved electroconductivity and a decreased production cost. Because an organic thin film transistor, which may be an device manufactured using such electroconductive polymer materials, may be easily manufactured using relatively simple printing technologies, the production cost thereof may be decreased, and because the organic thin film transistor has improved processibility and compatibility with flexible substrates, research on organic thin film transistors is being actively conducted. Currently, an organic thin film transistor may be used for devices for driving active displays and plastic chips for smart cards and inventory tags.
Such an organic thin film transistor may be necessarily required to protect an organic semiconductor layer from ambient air, e.g., oxygen or moisture, by finally forming a passivation layer. Currently, there may be no effective method of forming a passivation layer on an organic thin film transistor. A method of forming a passivation layer using inorganic materials, e.g., SiNx, and SiOx, through a chemical vapor deposition method or a sputtering method has been attempted. This method may be advantageous in that the film quality may be improved, but may be problematic in that the interfacial characteristics of the organic semiconductor may be deteriorated, forming a pattern through a solution process may be difficult, and performing a vacuum process and a high-temperature process may be difficult. In particular, this method may be problematic in that an organic semiconductor active layer may be deteriorated by active gas or plasma, and thus the performance of the organic thin film transistor may rapidly worsen.
A method of forming a passivation layer using polyimide, benzocyclobutene (BCB), and photoacryl has been attempted. However, in this method, because the heat-treatment temperature may be about 150° C. or more, an organic active layer may be rapidly deteriorated at increased temperatures, and thus this method may not be an effective method for forming a passivation layer of an organic thin film transistor. In particular, the most important problem in the method of forming a passivation layer of an organic thin film transistor using an organic film may be that the materials for forming the passivation layer may directly come into contact with an organic active layer, and thus the deterioration of an organic semiconductor active layer may be accelerated by an organic solvent.
As an example of methods of effectively forming a passivation layer using an organic film, there may be a method of forming a passivation layer using polyvinyl alcohol (PVA). However, this method may be chiefly used as a method of patterning pentacene, used as an organic semiconductor active layer. Further, in this method, the charge mobility after processing may be rapidly decreased to about ⅓. Accordingly, when a passivation layer is formed using an organic film or an inorganic film through the above methods, there may be a limit in that the initial performance of an organic thin film transistor may be maintained.